Chemical condensation process



Oct. 17, 1950 A. P. LIEN 2,525,810

CHEMICAL coNnENsATIoN PRocEss Filed Dec. 27, 194e HF STR/PPE? atented Oct. 17, 195() 2,525,810 CHEMICAL CONDENSATION` PROCESS Arthur P. Lien, Hammond, Ind., assignor to Standard il Company, Chicago, Ill., a corporation of Indiana Application December 27, 1949, Serial No. 135,166

(Gl. ZBO- 670) 7 Claims.

This invention relates to a process for effecting the intermolecular chemical condensation of certain polycyclic aromatic hydrocarbons. More particularly it relates to a process for the separation of substantially I-IF-insoluble polycyclic aromatic hydrocarbons such as alkyl naphthalenes from their mixtures with saturated hydrocarbons by a process which involves intermolecular chemical condensation of said alkyl naphthalenes to produce HF-soluble polynuclear aromatic hydrocarbons Which are extracted from said saturated hydrocarbons, both the chemical condensation and extraction steps being performed in a medium consisting essentially of liquidanhydrous hydrogen iluoride which functions as a catalyst in the chemical reaction and a solvent in the extraction operation.

Although the literature has indicated that liquid hydrogen fluoride is a solvent in general for aromatic hydrocarbons, I have found that this is not true, strictly speaking. Thus, I have observed that monocyclic aromatic hydrocarbons are substantially insoluble in liquid hydrogen fluoride. Moreover, I have found, as more fully set forth in U. S. Patent 2,426,624, that polynuclear aromatic hydrocarbons of quinonoid structure exhibit substantial solubility in liquid hydrogen fluoride Whereas under similar conditions polynuclear aromatic hydrocarbons of benzenoid structure are substantially insoluble in liquid hydrogen fluoride. Examples of benzenoid type polynuclear aromatic hydrocarbons are alkyl naphthalenes and phenanthrene. Examples of quinonoid type polynuclear aromatic hydrocarbons are anthracene, pyrene and perylene.

An application of this invention is in the separaton of alkylnaphthalenes, particularly methylnaphthalenes, from hydroformer bottoms. The process of the present invention affords not only a method of separating certain aromatic hydrocarbons from saturated hydrocarbons but also leads to the production of valuable HF-soluble polynuclear aromatic hydrocarbons. The process of this invention may also be applied to effect the chemical condensation of alkylnaphthalenes concentrated in fractions derived from coal tar or by coal hydrogenation.

One object of my invention is to provide a process for effecting the intermolecular condensation of substantially I-IF-inscluble polynuclear aromatic hydrocarbons, preferably polynuclear aromatic hydrocarbons containing only one naphthalenic structure such as alkylnaphthalenes, employing a catalyst consisting essentially of liquid, substantially anhydrous hydrogen fluoride. Another object of my invention is to convert certain HFinsoluble polynuclear aromatic hydrocarbons by an intermolecular condensation reaction into I-lF-soluble polynuclear aromatic hydrocarbons which are separated from the reaction mixture as a solution in liquid hydrogen iluoride. An additional object of my invention is to effect separation of saturated hydrocarbons, which are insoluble in liquid hydrogen bons.

uoride, from certain HF-insoluble polycyclic aromatic hydrocarbons by the treatment of hydrocarbon mixtures containing both with a catalyst consisting essentially of liquid hydrogen fluoride under conditions adapted to elfect intermolecular chemical condensation of said aromatic hydrocarbons to form I-IF-soluble polynuclear aromatic hydrocarbons While avoiding substantial cracking of said saturated hydrocar- Another object of my invention is to provide a process for the separation of naphthalene from alkylnaphthalenes. These and other objects of my invention will become apparent from the ensuing description` of my invention read in conjunction with the accompanying figure.

I have discovered that HF-insoluble polynuclear aromaticlhydrocarbons such as alkylnaphthalenes in the presence of liquid substantially anhydrous hydrogen fluoride undergo intermolecular condensation reaction producing polynuclear aromatic hydrocarbons such as alkyl perylenes and even higher molecular Weight hydrocarbons and that therintermolecular condensation products exhibit preferential solubility in substantially liquid anhydrous hydrogen fluoride. Hydrogen and/or paraflinic hydrocarbon gases are also produced in the course of the reaction. The products of the condensation reaction may be removed from the reaction zone as a solution in liquid hydrogen iiuoride when the latter is ernployed in quantity sufficient to function not only as a catalyst but also as a solvent for the reaction products. When the amount of hydrogen fluoride employed is insufcient to extract the desired amount of polynuclear aromatic hydrocarbon condensation product from the reaction mixture, at least a part of the reaction mixture may be extracted with additional hydrogen fluoride either in the reaction zone or in a separate zone under conditions particularly favorable for the extraction operation.

Surprisingly, I have found that naphthalene does not undergo condensation under the conditions under which alkyl naphthalenes readily condense to form higher molecular Weight hydrocarbons.

I have made the unexpected observation that mixtures of saturated hydrocarbons and I-IF-insoluble polycyclic aromatic hydrocarbons such as alkylnaphthalenes may be treated with a catalyst consisting essentially of liquid, substantially anhydrous hydrogen fluoride under certain operating conditions to 'effect intermolecular chemical condensation of said alkylnaphthalenes Without simultaneously effecting substantial cracking of said saturated hydrocarbons, although treatment of saturated hydrocarbons with liquid hydrogen fluoride under the same operating conditions in the absence of said alkylnaphthalenes would result in appreciable or substantial cracking of said saturated hydrocarbons. In other words, the intermolecular chemical condensation of I-IF-insoluble alkylnaphthalenes in `a mixture thereof With satuare methyland ethylnaphthalenes.

rated hydrocarbons, such as paraflins, can be made to proceed preferentially in the presence of a liquid substantially anhydrous hydrogen fluoride catalyst under reaction .conditions which would otherwise be suitable for effecting substantial cracking of saturated hydrocarbons. By liquid, substantially anhydrous hydrogen fluoride I mean hydrogen fluoride which may contain up to about 10 weight per cent of water, but which preferably contains 5 weight per cent or less, e. g. l or 2 weight percent, of Water.

Y When alkylnaphthalenes and the like containing relatively large alkyl groups, e. g. containing y5 or more carbon atoms, are subjected to the process of this invention, they tend to produce paraffin hydrocarbons. having the same or a lesser number of carbon atoms than were present `in the alkyl group, as well as intermolecular condensation products.

Suitable I-IF-insoluble polycyclio aromatic hydrocarbons which may be subjected to intermolecular chemical condensation in accordance with this invention are alkylnaphthalenes, such as methylnaphthalenes, ethylnaphthalenes, proplynaphthalenes, n butylnaphthalenes, secbutylnaphthalenes, tert-butylnaphthalenes, amylnaphthalenes, octylnaphthalenes, decylnaphthalenes, dodecylnaphthalenes, dimethylnaphthalenes, dipropylnaphthalenes, trimethylnaphthalenes and the like. Preferred charging stocks I may employ the pure polycyclic aromatic hydrocarbons or mixtures thereof as charging stocks or I may employ commercially available fractions containing these and similar polycyclic aromatic hydrocarbons, e. g. alkyl phenanthrenes and the like.

Suitable temperatures for effecting the inter-- molecular chemical condensation reaction fall between about 150 F. and about 450 F. However, the rate of the condensation reaction at temperatures below about 250 F. is too slow to be of practical signicanceand I have found it preferable to use temperatures of at least about 250 Ordinarily I prefer to effect the intermolecular condensation reaction at temperatures between about 300 F. and about 450 F., for example at a temperature of about 330 F.

Sufficient pressure is employed in effecting the intermolecular condensation reaction to maintain at least a substantial proportion of the reactants and catalyst in the liquid phase. Suitable pressures usually fall between about 50 and about 1500 p. s. i.

Hydrogen fluoride may be used in amounts between about 0.5 and about 25 or even a greater number of parts by weight (calculated as 100 per cent EF) per part by weight of chemically condensable polycyclic aromatic hydrocarbon in the charging stock. Ordinarily I prefer to employ between about l and about 15 parts by weight or" liquid substantially anhydrous hydrogen fluoride per part 0f condensable aromatic hydrocarbon. rThe hydrogen fluoride employed for the purposes of the present invention should contain at least about 90 per cent by weight o`f hydrogen fluoride. I prefer to employ commercial anhydrous hydrogen fluoride which usually contains at least about 98 per cent by weight of hydrogen fluoride.

rEhe time of reaction will be correlated with the other reaction variables to secure the desired extent of intermolecular condensation. Ordinarily I may employ reaction periods varying 4 between about 0.1 and about 4 hours, preferably about 0.3 toabout 2 hours.

It is desirable to effect intimate contacting of .the liquid hydrogen iiuoride or other catalyst with the reactants. Conventional equipment can be used to effect the necessary contacting in the course of the intermolecular condensation reaction, for example stirring and pumping equipment such as has been employed heretofore in effecting alkylation of isoparains with oleflns in the presence of a liquid hydrogen fluoride catalyst. rThe condensation reaction may be carried out as a batch, semi-continuous or continuous process. Both chemical condensation and extraction may bev effected simultaneously by continuously counterowing a hydrocarbon charging stock and liquid hydrogen fluoride catalyst through a vertical tower which may be packed, if desired, with HTF-resistant materials to provide for intimate intermingling of the counternowing streams. In another mode of operation the hydrocarbon charging stock may be caused to flow upwards through a pool of liquid hydrogen fluoride maintained in the reaction zone, when the temperature of operation is such that the hydrogen fluoride phase is the more dense phase.

Following the chemical condensation operation o-r in some instances simultaneously therewith, steps are taken to effect the extraction of polynuclear aromatic hydrocarbons produced in the condensation reaction, the extraction being effected with liquid substantially anhydrous hydrogen fluoride. It may be preferred to effect the condensation reaction and the solvent extraction operation under different operating conditions. Thus while it is ordinarily desirable to eect intermolecular condensation of alkyl naphthalenes with liquid hydrogen fluoride as the catalyst at temperatures above about 250 F. it is usually desirable to effect extraction of the resultant HF-soluble polynuclear aromatic hydrocarbons from the reaction mixture at temperatures below about for example temperatures between about 30 F. and 150 F., preferably between about 40 F. and about 100 F. A suitable extraction operation can usually be effected at about room temperature. Furthermore it may be desired to effect the solvent extraction operation with a higher HF:alky1naphthalene ratio than that employed in the chemical condensation step. Thus it may be desirable to effect the condensation reaction employing an I-IFzalkylnaphthalene weight ratio between about 0.5 and 1 whereas the ratio for the extraction operation can be higher, for example as high as 3 or even 5. In the condensation reaction which is effected at relatively high temperatures the possibility exists Vthat the employment of a very high I-IFzalkylnaphthalene ratio may result in the cracking of some of the saturated hydrocarbons, whereas at the relatively low temperature usually employed in the extraction operation, even very high HF: alkylnaphthalene ratios will not induce substantial cracking of saturated hydrocarbons.

The extraction operation will be effected under pressure suiiicient to maintain the liquid phase in th-e extraction zone. Usually I may employ pressures between about 5 and about 100 p. s. i. The extraction operation may be effected in conventional equipment such as is normally employed to effect selective solvent extraction of petroleum oils.

Referring to the figure, a suitable hydrocarbon charging stock comprising saturated hydrocaraseasi bons and an PIF-insoluble alkylnaphthalene, e. g., a hydroformer bottoms fraction containing methylnapthhalenes, is passed from source I through line Il into heater l2 wherein it is heated to a suitable temperature, for example between about 150 F. and about 450 F., preferably between about 300c F. and 350 F. From the heater, the hydrocarbon charging stock passes into reactor i3 which is provided with agitating means such as a mechanical stirrer M and a temperature control jacket i5. Liquid, substantially anhydrous hydrogen fluoride is passed in an amount between about and about 200 volume percent,` based on total feed` stock, from storage tank IE through valved line il and heater I8 into reactor 3. Suiiicient pressure is maintained in the reactor to hold the hydrocarbon reactants and the hydrogen iiuoride catalyst for the most part in the liquid phase. The back pressure on the reactor is controlled by a pressure control valve I9 in vent line 20. The pressure tends to increase during the course or the intermolecular condensation reaction since `it proceeds with the evolution of hydrogen and/or paraffinic hydrocarbon gases.

Upon completion of the desired reaction the reaction mixture is withdrawn from reactor i3 through line El and line 22 into settler 23. It desired, the settler may be operated under substantiailly the same conditions of temperature and pressure as those maintained in the reactor. Usually, however, it is desirable to operate the settler at a lower temperature and a correspondingly lower pressure. To this end it is usually desirable to withdraw at least a portion of the reaction mixture through valved line 24 and cooler 25 to adjust the temperature of the reaction mixture to a suitable value, usually below about 150 F., for example, about room temperature, before passing the mixture into the settler. The pressure in the settler is controlled by pres- Sure control valve 20 in vent line 2l. In order to facilitate the settling and extraction which occur in settler 23 it may be desirable to add liquid hydrogen iluoride thereto through valved line 28 which is connected to valved line l'i leading from HF storage tank I6. In the settler a gas stream comprising hydrogen and/or paramnic hydrocarbon gases is withdrawn through vent line` 2l. An upper raffinate phase 29 comprising saturated hydrocarbons and unconverted HF-inscluble polycyclic aromatic 'hydrocarbons is formed; this phase is withdrawn through line` 30, whence all or a portion thereof may be withdrawn through valved line 3l for recycle to line il and heater l2 to reactor i3. Part or all of the ranlnate phase may be withdrawn through valved line 32. i i

A lower extract phase 33 comprising hydrogen fluoride and extracted hydrocarbons such as quinonoid-type polynuclear aromatic hydrocarbons and HF-soluble polynuclear aromatic hydrocarbons produced by the condensation reaction `is formed in settler 23. The extract phase is withdrawn through valved line 3ll,`whence part or all thereof may be passed into line 3l for recycle to reactor i3. Usually it is undesirable to allow the hydrocarbon concentration of the hydrogen iluoride in the reactor to exceed about 40 weight per cent since an excessive amount of hydrocarbon in solution in the HF. tends to reduce or impair its catalytic activity.

For this reason and for the further reason that it is usually desired to recover the polynuclear aromatic hydrocarbon formed in the intermolec- Yand heater 36 into tower 31 6i. ular condensation reaction, at least a part of the extract phase in the reactor 23 is continuously or intermittently withdrawn through valved line 35 wherein HF V'is stripped from the extract phase. Temperatures between about 150 and about 500 F. and relatively low pressures such as 50 p. s. i. g. or even lower are maintained in tower 31. If desired, a stripping gas may be introduced by line- 331into the lower portion of the tower to aid inthe vaporiZa-tion of the hydrogen iiuoride. Suitable stripping gases comprise light parailinl hydrocarbons such as methane, ethane, propane, n-butane, isobutane, pentanes and the like. Hydrogen iluoride-soluble aromatic hydrocarbons are withdrawn from tower 31 through valved line 39. A `vapor stream comprising hydrogen iiuoride is withdrawn from tower 3T through valved line 40 whence it may be passed through condenser 4l and line 42 into HF storage tank i6. `l/Vhen a stripping gas is employed in tower 3i' to aid in the vaporization of hydrogen fluoride it mayI be desirable to divert a portion of the gas stream from line 40 into valved line i3 and condenser M to liqueiy its hydrogen fluoride content; from condenser del the gas-liquid mixture is passed into an accumulator drum 45, whence stripping gas is diverted through valved vent line 46 and liquid hydrogen uoride is passed through valved line #il which leads into line i2 passing into the hydrogen iiuoride storage tank I6. The hydrogen iluoride storage tank is provided with a valved vent line 48 through which Volatile materials which tend to accumulate in the system may be removed from time to time. Part or all of the stripping gas may be recycled from line 46 to line 33 leading into tower 3l.

Although it will be desirable to strip hydrogen fluoride from the extract phase by vaporization in large scale operations, in small or batch scale operations it may be more desirable simply `to dilute the extract phase with water or to dilute it with alkaline solutions whereupon the hydrocarbon materials contained in the extract phase will form a distinct phase which can be separated and utilized as desired. The disadvantage of this method of operation, of course, is that the hydrogen fluoride is of no further use in the condensation reaction.

The oil fractions having relatively high concentrations of saturated hydrocarbons leaving the system through line 32 are adaptable to many uses depending upon their boiling ranges, viscosities and other properties.

The hydrogen iluoride-soluble materials leaving the reaction system through line 39 comprise not only polynuclear aromatic hydrocarbons but also certain of the oleiinic, sulfur, nitrogen and oxygen compounds that may have been present in the charging stock. The polynuclear aromatic materials withdrawn through line 39 may be ci value as chemical raw materials for such processes as oxidation, halogenation, nitration, sulfonation, amination, etc.; they may also be of value as i insecticidal materials, plasticizers for natural or synthetic rubbers, vinyl resins, etc.

The specic examples presented in thefollowing table will serve to illustrate the principles and some applications of the process of this invention, but it is not intended that they .should serve unduly to limit the invention. The hydro-- gen fluoride employed in catalyzing the conden sation reactions and toeiect the extractionwas commercial liquid. substantially anhydroushyii drogen fluoride. The reactions were effected by cur under these conditions. Run 2 also indicates intimately agitating the liquid hydrogen fluoride Very'clearly that monocyclic aromatlc hydrowith the charging stocks in a carbon steel pressure carbons do not, undergo intermolecular condensavessel having a capacity of 1575 cc., provided with tion to| form HF-soluble polynuclear aromatic a stirrer which was operated at about 1725 5 hydrocarbons even under relatively stringent ep-A R. P. M. during the reaction period. Following erating conditions.

stirring of the reactants for a period of time indi- Run 3 shows that a dicyclic benzenoid hydrocated in the table as contact time, stirring was carbon, specifically amylnaphthalene, remains discontinued and liquid phases were allowed to substantially undissolved in liquid hydrogen separate in the pressure vessel by gravity settling. 10 fluoride at room temperature. This run also When the reaction temperature was above roorn indicates that more stringent operating conditemperature, the high temperature contacting tions are necessary to effect intermolecular chemwas followed by a settling period at room temical condensation reactions with this hydrocarperature. bon. No cracking was observed to occur in this Run 1 indicates that Xylene, which may be 15 run. taken as typical of monocyclic aromatic hydro- Runs 4 and 5 show that negligible, if any, conoarbons, is substantially insoluble in liquid hydrodensation of naphthalene was induced by hydrogen fluoride at moderate temperatures. It was gen fluoride at 212 F'. and 330 F. The lili-solalso obvious that no cracking had occurred in uble materials produced in these runs are probthis run. 20 ably impurities extracted from the naphthalene Run 2 indicates that even at the high temperafeed stock. In marked contrast is the behavior ture of 330 F. and the extended contacting period of l-methylnaphthalene in run 6, wherein it was of 3 hours, liquid hydrogen fluoride dissolves subshown that 24 weight percent of the charging stantially no toluene from its solution in nstock was converted to HP1-soluble intermolecuheptane. Also notable is the fact that 20 volume 25 lar chemical condensation products at 330 F. per cent of toluene completely inhibited the The average molecular weight of the BIF-soluble cracking of n-heptane which would otherwise o'cmaterial produced in run 6 was about 425.

Run No l 2 3 4 5 6 7 Y 8 Feed:

Aromatic xy1ene to1uene amyl-napthaelene. napthalene-. napthalene l-methylnaptbalene. 2-methy1napthalene Diluent nheptane n-heptane. n-hcptane n-heptane n-heptane n-heptane n-heptaue. benzene. Volumepercent 80 80 80 83 22 88 80 85.

duuencmfeed. HF,volumepercent 20 20 20 30 30 36 2n 45.

on feed. Reeet1ontemp.,F. 70-80 3301 70-80 2121 3301 3301 3321 250.1 Contact time, HrS.-. 0.33 2 0.33.." 2 i 1 i 3. Refractve index Feed 1.4107 Rafiinate.- l.4ll2 Feed solution l.4091. 1.4280. 1.4332 R'linate solu- 1.4091..." l.4282 1.4234...

'1011. Puredi1ueut 1.3890.. 1.3890...- 1.3890... 1.3890. Weightper cent 0 0.0 0.0 0 0.

cracking products` Aromatic removal, weight per cent:

oneven 0 0 0.0... 22.2 0. Onactualweght. 0 20....' 1 2' 24 26.0.. 13.4.

1 Cooled to room temperature (70-75 F.) to separate phases.

Run Ne 9 10 11 12 13 14 15 16 Hydroformer Bottoms Fractions Feed:

Aromatic 2-methy1- none.. amyltota1 332-495o F 495600 F 495-000F.1 600 F.Bottoms.

naphnaphthalcne. thalene. Diluent cetane octane. none n-heptanen-heptane2. n-heptane2. n-heptane2 n-heptane.2 Volume per cent dilucnt 84 80 80 80 80.

in feed. HF, volume per cent onf ecd 20 20 20 20. Reaction temp,y F 70-80 70-80 212 3 70-80. Contact time, Hrs... 0 i2 0.33 4R 0. 33. Refractive index (n):

Feed... 1.5948 1.5672 1.5980 1.71751 Remnefe 1. 5805 1. 560 1. 5719- 1. e303 1 Feed solution 1.4327 1.4350- 1,4418 1.4019 Refimeteselutien 1.4282---- 1.4340 1.4230 1. 4288 Pure di1uent 1 3800 1.3980 1.3930 1. 3980 Weight per cent products. Aromatic removal, Weight per cent:

011mm 46.4 11.2 2.7 4,1 31.5 52.0. Onactualweight 57.0 7734 11.5 40 56.0 Specific Dispersion:

Feed... 234 2211 271 271 550.15 Rqmmfe 247 230 266 234 327.

1 Reaction mixture derived from run 14.

2 Contains 10% benzene.

3 Cooled to room temperature (7G-75 F.) to separate phases. 4 24% of this extract boiled below feed.

Calculated.

Runs '7, 8 andl 9 were conducted upon Z-methylnaphthylene as the charging stock. In run 7, Where n-heptane was the diluent, considerable chemical condensation occurred, as will be evident from the data concerning aromatic removal presented in the table. In run 7, the molecular weights of the aromatic hydrocarbons in the feed, raffinate and extract phases, respectively, were 142, 175 and 317. The molecular weight of the extracted aromatic hydrocarbon mixture indilcates that it contains a considerable proportion of a dimer derived from the methylnaphthalene charging stock and also some higher molecular weight condensation products.

In run 8 where the diluent was benzene, considerable condensation was shown to occur.

Run 9 like run '7 shows that intermolecular chemical condensation of an 11F-insoluble alkylnaphthalene can be readily effected in the presence of a saturated hydrocarbon having a relatively long chain which, as run l demonstrates, would undergo extensive cracking in the absence of polycyclic aromatic hydrocarbon. A comparison of run 9 with run l shows that a shorter contact time can be balanced or even overbalanced by the use of a larger amount of HF to effect the intermolecular condensation. Shortening the time in run 9 to 1/6 of that in run 7 but increasing the amount of hydrogen fluoride by lll-fold under otherwise similar operating conditions resulted in more extensive conversion and extraction in run 9 than were obtained in run 7.

The following is an analysis of the cracked products obtained from run 10.

n Wm be noted that although in run 1o extensive cracking of the cetane occurred, substantially no cracking occurred in run 9.

Run 11 is illustrative of the intermolecular chemical condensation of a higher alkyl naphthalene, viz. a mixture of amyl naphthalenes. The results of this run indicate that a considerable amount of side chain scission occurred in addition to the condensation of aromatic nuclei to produce HF-soluble polynuclear aromatic hydrocarbons.

The charging stock in run No. 12 was hydroformer bottoms containing hydrocarbons boiling from 332 F. to about 800 F. This run indicates that about 11 per cent of the total hydroformer bottoms was extracted by liquid hydrogen fluoride at about room temperature, Since the ratnate phase derived from run 12 has a considerably lower refractive index than the charging stock, this indicates that polycyclic aromatic hydrocarbons more highly condensed than naphthalenes are being removed as a solution in the liquid hydrogen fluoride. lin order to study this phenomenon further the hydroformer bottoms was divided into two distillate fractions boiling, respectively, in the range 332 to 495 F. and 4:95

10 to `600 F. and a` residual fraction boiling from 600 F. to the `end boiling point of the hydroformer bottoms. The n-heptane diluent of runs 13-16, inclusive, contained about l0 volume per cent of benzene.

Runs 13 and 14 indicate that fractions of the hydroformer bottoms comprising predominantly alkyl dicyclic aromatic hydrocarbons, .fpecically methylnaphthalenes, do not dissolve appreciably in liquid hydrogen fluoride at moderate temperatures. The amount of aromatics extracted in run 16 from the `highest boiling fraction of the hydroformer bottoms `is in sharp contrast to the amounts of extract obtained in runs i3 and 14. The high degree of extraction obtained in run 16 is explainable on the basis that the fraction of hydroformer bottoms employed as the charging stock in that run contained substantial quantities of tricyclic quinonoid-type aromatic hydrocarbons such as anthracene and alkyl anthracenes.

However, an HEY-insoluble fraction containing monoand dimethyl naphthalenes can be subjected to high temperature intermolecular condensation in the presence of HF, as in run l5, thereby producing ELF-soluble polynuclear aromatic hydrocarbons. A comparison of run l5 with run 7 indicates that it is desirable to employ higher temperatures than 212 F., since at higher temperatures the intermolecular condensation reaction proceeds at a far greater rate. Run 15 also `shows that by the process of this invention it is possible to separate 11F-insoluble polycyclic aromatic hydrocarbons from HF-insoluble monocyclic aromatic hydrocarbons.

From the foregoing description of my invention, it Will be apparent that it is capable of considerable variation. Thus, naphthalene or phenanthrene may be alkylated, for example, methylated, ethylated, butylated, etc., to convert them to condensable hydrocarbons which may thereafter be subjected to the above described HF- catalyzed condensation process.

This application is a continuation-in-part of Serial No. 760,061, filed by me on July l0, 1947.

Having thus described my invention, what I claim is:

1. A process for effecting the intermolecular chemical condensation of an alkyl naphthalene, which process comprises contacting an alkyl naphthalene with a catalyst consisting essentially of liquid substantially anhydrous hydrogen fluoride at a temperature between about F.

and about 450 F. under pressure sufficient to,

maintain the liquid phase for a period of time sufficient to effect substantial interniolecular chemical condensation, and separating condensation products thus produced.

2. A process for effecting the intermolecular chemical condensation of an alkyl naphthalene, which process comprises contacting an alkyl naphthalene with between about 0.5 and about 25 parts by weight of a catalyst consisting essentially of liquid substantially anhydrous hydrogen uoride under pressure suilicient to maintain the liquid phase at a temperature between about 250 F. and about 450 F. for a period of time suiiicient to effect intermolecular chemical condensation, and separating condensation products thus produced.

3. The process of claim 2 wherein the alkyl naphthalene is a methyl naphthalene.

4. The process of claim l2 wherein the alkyl naphthalene is an amyl naphthalene.

5. A process for efecting the intermolecular chemical condensation of an alkyl naphthalene,

l1 which process comprises contacting an alkyl naphthalene with between about 0.5 and about 25 parts by weight of a catalyst consisting essentially of liquid substantially anhydrous hydrogen fluoride under pressure suicient to maintain the liquid phase at a temperature between about 250 F. and about 450 F. for la period of time suiiicient to eiect intermolecular chemical condensation, cooling the reaction mixture to a temperature between about 30 F. and about 150 F. to produce a predominantly hydrocarbon layer and a layer comprising predominantly liq- .uid hydrogen fluoride containing dissolved intermolecular chemical condensation products, and separating the layers.

6. A process for the separation of a mixture containing a substantially HF-insoluble alkyl naphthalene and a saturated hydrocarbon without substantial cracking of said saturated hydrocarbon, which process comprises contacting said mixture with a catalyst consisting essentially of liquid substantially anhydrous hydrogen fluoride under a pressure suicient to maintain the liquid phase at a temperature between about 250 F. and about 450 F. whereby intermolecular chemical condensation of said alkyl naphthalene occurs to form a polynuclear aromatic hydrocarbon having substantially greater solubility in liquid substantially anhydrous hydrogen fluoride than said alkyl naphthalene and producing a saturated hydrocarbon having a reduced content of HF-lnsoluble polycyclic aromatic hydrocarbon from the reaction mixture by extraction of said saturated hydrocarbon with liquid substantially anhydrous hydrogen fluoride.

'7. A process for the separation of a mixture containing a substantially I-IF-insoluble alkyl naphthalene and a saturated hydrocarbon without substantial cracking of said saturated hydrocarbon, which process` -comprises contacting said mixture with between about 0.5 and about parts by weight of a catalyst consisting essentially of liquid substantially anhydrous hydrogen fluoride under a pressure sufficient to maintain the liquid phase at a temperature between about 250 F. and about 450 F. for a period of time sufcient to effect intermolecular chemical condensation of said alkyl naphthalene to form a polynuclear aromatic hydrocarbon having substantially greater solubility in liquid substantially anhydrous hydrogen fluoride than said alkyl naphthalene, and producing a saturated hydrocarbon having a reduced content of HF-insoluble alkyl naphthalene from the reaction mixture by eX- tracting at least a portion of said reaction mixture with liquid substantially anhydrous hydrogen fluoride at a temperature between about F. and about 150 F.

ARTHUR P. LIEN.

No references cited. 

1. A PROCESS FOR EFFECTING THE INTERMOLECULAR CHEMICAL CONDENSATION OF AN ALKYL NAPHTHALENE, WHICH PROCESS COMPRISES CONTACTING AN ALKYL NAPHTHALENE WITH A CATALYST CONSISTING ESSENTIALLY OF LIQUID SUBSTANTIALLY ANHYDROUS HYDROGEN FLUORIDE AT A TEMPERATURE BETWEEN ABOUT 150*F. AND ABOUT 450*F. UNDER PRESSURE SUFFICIENT TO MAINTAIN THE LIQUID PHASE FOR A PERIOD OF TIME SUFFICIENT TO EFFECT SUBSTANTIAL INTERMOLECULAR CHEMICAL CONDENSATION, AND SEPARATING CONDENSATION PRODUCTS THUS PRODUCED. 